The present invention relates to a stress composite sensor and a stress measuring device using the same for a structure, for measuring stresses, such as shearing stresses, or shearing strains, produced in a structure such as an automobile, airplane, railroad vehicle, crane, robot or the like.
Methods for measuring stresses, such as shearing stresses, or shearing strains, produced in a structure such as an automobile, airplane, railroad vehicle, crane, robot or the like, include the photoelasticity method, brittle coating method, acoustic method, holographic method and strain gauge method, of which generally the strain gauge method has been used most frequently.
Such mechanical quantity sensors are various in kind and easy to handle, but when used for measuring stresses, they have to be equipped with transducers. Further, in the strain gauge method, the strain gauge is subjected to stresses in every direction and hence analysis is required.
Further, a stress sensor comprising a conventional mechanical quantity sensor such as a strain gauge, when singly used on a structure, receives greater amounts of other stresses than the main stress depending upon the position where it is attached; thus, a plurality of stress sensors have to be used and such stress sensor has to be attached to the neutral point where other stresses than the main stress are not transmitted or reduced, making it necessary to find the neutral point possessed by the structure and to attach a stress sensor to the neutral point accurately.
With the above in mind, the present invention provides an arrangement wherein instead of singly using stress sensors (mechanical quantity sensors) comprising strain gauges, a plurality of stress sensors are composited or integrated to provide an integral stress composite sensor, which is mounted on a structure such as an automobile whose stresses are to be measured, and X-, Y- and Z-axis direction stress signals obtained from the single-packaged stress composite sensor are selectively used to measure stresses.
The present invention includes a plurality of stress sensors or a plurality of rows of stress sensors comprising strain gauges are integrated by being fixed on the same plane of a base plate at intervals, so that each stress sensor delivers stress signals in one direction alone or a selected stress sensor delivers stress signals in one direction alone.
The present invention provides stress sensors comprising strain gauges fixed on the individual surfaces of base plates placed in two mutually orthogonal planes and thereby integrated to provide a sensor segment, a plurality of such sensor segments or a plurality of rows of such sensor segments being connected together or superposed and connected together to form an integral body, so that each sensor segment delivers stress signals in two directions or a selected sensor segment delivers stress signals in two directions.
The present invention also provides stress sensors comprising strain gauges fixed on the individual surfaces of base plates placed in three mutually orthogonal planes and thereby integrated to provide a sensor segment, a plurality of such sensor segments or a plurality of rows of such sensor segments being connected together or superposed and connected together to form an integral body, so that each sensor segment delivers stress signals in three directions or in selected directions or a selected sensor segment delivers stress signals in three directions.
The present invention further provides a signal processing circuit such as a bridge circuit of strain gauges or an amplifying circuit integrally formed on the same base plate as that of a stress composite sensor as described above.
The present invention still further provides for a hole formed in the stress concentration region of a structure whose stresses are to be measured and a stress composite sensor being selectively installed, so that X-axis, X- and Z-axis or X-, Y- and Z-axis direction shearing strains produced in the structure are selectively measured corresponding to the selected stress composite sensor.
The present invention additionally provides a stress measuring device for a structure described above, when shearing strains produced in the structure are to be sensed, at least one or more necessary sensors or sensor segments of the stress composite sensor being sorted for stress measurement.
The present invention yet further provides a stress composite sensor as described above being selectively installed in a hole formed in the stress concentration region of a structure whose stresses are to be measured, thereby making it possible to measure stresses in a particular direction or summed stress signals from a plurality of sorted sensor segments by means of sorted stress signals in the X- and Y- axis or X-, Y- and Z-axis directions of the structure.
The present invention further still provides a stress composite sensor as described above being installed in a hole formed in the stress concentration region of a structure whose stresses are to be measured, and the stress sensors in a plurality of selected sensor segments alone in the X-axis, X- and Y-axis or X-, Y- and Z-axis directions of the structure are employed for sensing and their stress signals are separated according to the X-, Y- and Z-axis directions, such separated stress signals being respectively added together to provide stress signals which are subjected to comparative computation for stress measurement.
The present invention also provides in a stress measuring device for a structure described above, when a necessary sensor segment is sorted for stress measurement, a plurality of stress signals of the sensor segments along a stress layer having relatively little mixing of other stresses produced in the structure being derived and combined for stress measurement.
The present invention also provides in a stress measuring device for a structure described above, stresses in the X- and Z-axis or X-, Y- and Z-axis directions being sorted to measure stresses in the necessary directions, the resulting stress signals being used as control parameters.
According to the invention, a plurality of stress sensors or a plurality of rows of stress sensors comprising strain gauges are integrated by being fixed on the same base plate, whereby each stress sensor in the single package delivers signals in one direction alone or a selected stress sensor delivers stress signals in one direction alone, and hence stresses in one direction can be measured.
According to the present invention, stress sensors comprising strain gauges are fixed on the individual surfaces of base plates placed in two mutually orthogonal planes and thereby integrated to provide a sensor segment, a plurality of such sensor segments or a plurality of rows of such sensor segments being connected together or superposed and connected together to form an integral body, so that each sensor segment in a single package delivers stress signals in two directions or a selected sensor segment delivers stress signals in two directions alone and hence stresses in two directions can be measured.
According to the present invention, stress sensors comprising strain gauges are fixed on the individual axis surfaces of base plates placed in three mutually orthogonal planes and thereby integrated to provide a sensor segment, a plurality of such sensor segments or a plurality of rows of such sensor segments being connected together or superposed and connected together to form an integral body, so that each sensor segment in a single package delivers stress signals in three directions or a selected sensor segment delivers stress signals in three directions. Thus, stresses in three directions can be measured.
According to the present invention, a signal processing circuit such as a bridge circuit of strain gauges or an amplifying circuit is integrally formed on the base plate for the stress sensor or sensor segment; thus, the measuring function can be improved to increase reliability.
According to the present invention, a single-packaged stress composite sensor described in claims 1 through 4 is selectively installed in a hole formed in the stress concentration region of a structure, whereby X-axis, X- and Z-axis or X-, Y- and Z-axis direction shearing strains produced in the structure or 1-, 2- or 3-direction stresses corresponding to the selected stress composite sensor can be selected and measured.
According to the present invention as described above, when shearing strains produced in a structure are to be sensed, at least one or more necessary sensors or sensor segments of the stress composite sensor are sorted for stress measurement, whereby stresses in any desired direction and an amount of change in said stresses can be derived and accurately measured.
According to the present invention as described above, a stress composite sensor capable of measuring stresses in a single direction or a plurality of directions is selectively installed in a hole formed in the stress concentration region of a structure, whereby stresses in a particular direction or summed stress signals from a plurality of sorted sensor segments can be derived by means of sorted stress signals in the X-axis, X- and Z-axis or X-, Y- and Z-axis directions of the structure and thus stresses can be measured.
According to the present invention as described above, a stress composite sensor capable of measuring stresses in a single direction or a plurality of directions is installed in a hole formed in the stress concentration region of a structure, and a plurality of selected sensor segments alone in the X-axis, X- and Y-axis or X-, Y- and Z-axis directions are employed for sensing and their stress signals are separated according to the X-, Y- and Z-axis directions, such separated stress signals being respectively added together for comparative computation of the resulting stress signals so as to measure stresses with increased accuracy.
According to the present invention as described above, in a stress measuring device for a structure described above, when necessary sensor segments are sorted for stress measurement, a plurality of stress signals of the sensor segment along a stress layer having relatively little mixing of other stresses produced in the structure are derived and combined for stress measurement; thus, stresses not influenced by cross talk are easily measured.
According to the present invention as described above, in a stress measuring device for a structure described above, stresses in the X- and Z-axis or X-, Y- and Z-axis directions are sorted to measure stresses in the necessary directions, the resulting stress signals being used as control parameters; thus, it is possible to construct a highly reliable control system adapted to accurately derive stresses in necessary directions alone.